In the US, more people work in private security than in all police forces combined, yet public debate about crime prevention typically looks at the use of public resources to deter, incapacitate, or rehabilitate criminals. This column calls for more discussion of how private action can make policing more effective and reduce the profitability of crime. One such experiment – “business improvement districts” in Los Angeles – has generated remarkable social benefits.

Potential victims often ward off crime by taking appropriate precautions. This column argues that government policy targeted at strengthening the precautionary response of potential victims can make a big difference. It shows that mandating the installation of burglar-resistant features in residential construction in the Netherlands reduced burglary risk by 26%.

According to the US Department of State, there are more than 12 million victims of human trafficking worldwide. This column presents a new index to measure the spread of anti-trafficking policies. It suggests they mainly diffuse across contiguous countries and main trading partners, due to externality effects, and also via political and cultural similarities, due to learning and emulation.

Does it pay to be corrupt? This column presents evidence from 22 emerging economies in Europe and the former Soviet Union on the effects of corruption on firm productivity. It finds that in a highly corrupt country, bribing officials actually has a negative effect on productivity, whereas in countries with strong institutions, it can open doors that competitors dare not touch.

How economically minded are car thieves? This column presents evidence from the Netherlands suggesting that car thieves stay away from cars in unpopular colours because of their relatively low resale value. It argues that driving a car in a bright, uncommon colour such as yellow is a highly effective deterrent against car theft – about as effective as an expensive security device.

The opening of a casino on an American Indian reservation in North Carolina offered a natural experiment to examine the impact of changes in household income on children’s later life outcomes, particularly their educational attainment and involvement in crime. In an interview recorded at the annual congress of the European Economic Association in Milan in August 2008, Randall Akee of IZA talks to Romesh Vaitilingam about the findings.

China’s one-child policy led to an explosion of the boy-girl ratio in the ‘80s and ‘90s. As this “only child” generation reaches adulthood, problems – including rising crime rates – are starting to appear.

Crime rises when US welfare recipients run short of cash at the end of the month. This column discusses research that links the timing of financially-motivated crime and the timing of welfare payments. Cities that make monthly welfare payments see a clear monthly crime cycle, whereas cities that spread out the payments do not.

The importance of environment and how workers affect the productivity of co-workers through learning valuable skills and work habits is often stressed, but whether employees sometimes learn unethical practices from their peers in order to boost productivity is less well documented. The authors of CEPR DP6550 find that once a worker adopts questionable methods - which seem to be effective, competitive pressures may lead others to follow in order to get ahead, or perhaps just to stay even with other workers who are adopting similar techniques.

The reverse causality problem makes it difficult to test empirically the impact of additional police on crime rates. The massive re-deployment of police after the July 2005 London bombings provides a natural experiment that gets around this. Results show that more police do indeed reduce crime.

Among the many factors that influence the decision to commit a crime, public law and sanctioning activity play a crucial role. The authors of CEPR DP6401 find that among their dataset in Italy an additional month of expected punishment reduces the propensity to recommit a crime by 1.24%.